Chemical preparation of the eye in ophthalmic surgery. III. Effect of povidone-iodine on the conjunctiva

In praise of povidone-iodine application in ophthalmology

Polyvinyl pyrrolidone or povidone-iodine (PVP-I) is a water-soluble complex formed by the combination of iodine and a water-soluble polymer, polyvinyl pyrrolidone. This complex exerts bactericidal, fungicidal, and virucidal action by gradually releasing free iodine at the site of application to react with pathogens. In ophthalmology, PVP-I is used as a disinfectant and antiseptic agent for preoperative preparation of the skin and mucous membranes and for treating contaminated wounds. PVP-I has been shown to reduce effectively the risk of endophthalmitis in various ocular procedures, including cataract surgery and intravitreal injections; however, it has also been used in the treatment of conjunctivitis, keratitis, and endophthalmitis, with promising results especially in low-resource situations. PVP-I has been associated with complications such as postoperative eye pain, persistent corneal epithelial defects, ocular inflammation, and an attendant risk of keratitis. In cases of poor PVP-I tolerance, applying PVP-I at lower concentrations or using alternative antiseptics such as chlorhexidine should be considered. We provide an update on the efficacy of PVP-I in the prophylaxis and treatment of conjunctivitis, keratitis, and endophthalmitis and a comprehensive analysis of the current literature regarding the use of PVP-I in the management of these ocular conditions. Also, PVP-I-related adverse effects and toxicities and its alternatives are discussed. The goal is to present a thorough evaluation of the available evidence and to offer practical recommendations for clinicians regarding the therapeutic usage of PVP-I in ophthalmology.

Prophylaxis of Ocular Infection in the Setting of Intraocular Surgery: Implications for Clinical Practice and Risk Management

In this review we discuss the role of intraocular surgery preoperative prophylaxis. The correct choice of antimicrobial drug is variable in each surgical setting, according to the available strengths of evidence, the anatomical district involved, and the type of procedure. In the ophthalmic surgical field, there has been a progressive shift from antibiotic formulations, which are known to cause antibiotic resistance, to a new class of antiseptic compounds, which proved to be effective not only against bacteria, but also against fungi, protozoa, and viruses. Among these, povidone-iodine (PVI) is a water-soluble polymer that can form a complex with iodine, and the perioperative application of PVI 5-10% eye drop for 3 min is the gold standard for infection prophylaxis. A new formulation of 0.6% PVI eye drop is a new option for infection prophylaxis in the days before surgery. Chlorhexidine is a biguanide compound, which is a valid alternative with a good safety and efficacy profile and is the antiseptic of choice in patients with iodine allergy. New compounds that are currently being studied include polyhexamethylene biguanide (PHMB), picloxydine, ozone, hypochlorous acid (HOCl), and Biosecur. PHMB is a biguanide polymer that was found to be more effective than PVI in in vitro studies for reducing microorganisms and extending the duration of antisepsis, but to date, there are no formulations available on the market for preoperative ocular surgery in which it is present as main ingredient. Ozone is a molecule with oxidizing effect, which showed interesting preliminary results but is not effective against virus, Staphylococcus aureus and Candida albicans. HOCl has a natural bactericidal propriety but its applicability to prophylaxis of ocular infection in the setting of ocular surgery is not established. Biosecur is a non-toxic organic alcohol-free compound that exhibited bactericidal and fungicidal effect versus all common microorganisms and is currently available as an ocular spray.

Doctor I Have an Iodine Allergy

Ophthalmologists frequently face patients who refuse asepsis protocols involving povidone-iodine (PI) due to claims of an allergy to iodine. Such patients usually base this claim on previous reactions to shellfish consumption or to imaging procedures that used iodine-based contrast agents. Allergy to iodine, however, is biologically impossible, and iodine deficiency causes severe developmental problems, including mental retardation. Furthermore, shellfish allergy is due to tropomyosins in muscle tissue, and reactions to intravascular contrast dyes are due to hyperosmolar solutions; neither “allergy” is due to iodine. PI, which contains 9–12% iodine, is the preferred antiseptic for ophthalmic procedures. Experience shows that PI can be administered safely to patients claiming iodine allergy. True allergy to PI is rare and, if indicated, skin patch testing can be performed prior to surgery. Patients who react adversely to highly concentrated (5–10%) PI usually experience toxicity to the corneal and conjunctival epithelium after topical administration. Dilute (0.1–0.25%) PI kills microbes quicker than higher concentrations but for shorter periods of time because the total dose of iodine is smaller. Repeated administration (every 20–30 s) of dilute PI effectively kills microbes for as long as necessary with little risk of epithelial toxicity.

The Search for Antifungal Prophylaxis After Artificial Corneal Surgery-An In Vitro Study

PURPOSE

To evaluate the antifungal properties of topical antibiotics (already being used successfully to prevent bacterial endophthalmitis) and some promising antiseptics for antifungal prophylaxis in the setting of artificial corneal implantation.

METHODS

Several commonly used antibiotics for antimicrobial prophylaxis after artificial corneal implantation, in addition to antiseptics [benzalkonium chloride (BAK), povidone-iodine (PI), and some ionic liquids (ILs)], were tested in vitro against Candida albicans, Fusarium solani, and Aspergillus fumigatus. The time-kill activity was determined. Toxicity was assayed in vitro on human corneal epithelial cultures using trypan blue. Adhesion and tissue invasion experiments were also carried out on porcine corneas and commonly used contact lenses, with or without gamma irradiation, and by analysis with fluorescence microscopy.

RESULTS

Polymyxin B (PMB)/trimethoprim/BAK (Polytrim), PMB alone, gatifloxacin with BAK (Zymaxid), and same-concentration BAK alone exhibited antifungal activity in vitro. Moxifloxacin (MOX) or gatifloxacin without BAK-as well as trimethoprim, vancomycin, and chloramphenicol-had no effect. 1% PI and ILs had the highest efficacy/toxicity ratios (>1), and Polytrim was species dependent. Subfungicidal concentrations of Polytrim reduced adhesion of C. albicans to Kontur contact lenses. Gamma-irradiated corneas showed enhanced resistance to fungal invasion.

CONCLUSIONS

Of antibiotic preparations already in use for bacterial prophylaxis after KPro surgery, Polytrim is a commonly used antibiotic with antifungal effects mediated by both PMB and BAK and may be sufficient for prophylaxis. PI as a 1% solution seems to be promising as a long-term antifungal agent. Choline-undecanoate IL is effective and virtually nontoxic and warrants further development.

Effect of topical povidone-iodine 10% plus levofloxacin 0.5% 1 hour before cataract surgery in eliminating perioperative conjunctival flora: randomized clinical trial

PURPOSE

To evaluate the effect of a single administration of topical povidone-iodine (PVI) 10% plus levofloxacin 0.5% at 1 hour before cataract surgery on perioperative elimination rate of conjunctival flora.

SETTING

Poostchi Ophthalmology Research Center, Shiraz, Iran.

DESIGN

Randomized controlled trial.

METHOD

Patients who required cataract surgery were randomly assigned to 1 of 2 groups: intervention (administration of PVI 10% plus levofloxacin 0.5% at 1 hour preoperatively) or control. The patients in both groups received PVI just before the operation. Conjunctival cultures were obtained using thioglycollate broth at 4 timepoints: T1, before intervention; T2, before the second application of PVI; T3, 3 minutes after the second administration of PVI; and T4, just postoperatively.

RESULTS

The study comprised 142 patients. The comparative rates of positive cultures in the intervention vs control groups were as follows: T1 (70.4% vs 73.2%, P = .709); T2 (15.5% vs 71.8%, P < .001); T3 (7.0% vs 19.7%, P = .027); and T4 (5.6% vs 4.2%, P = .698). Coagulase-negative Staphylococci was the most common isolated microorganism.

CONCLUSIONS

Results showed that a single adjuvant application of PVI 10% plus levofloxacin 0.5% eyedrops at 1 hour before operation leads to a further increase in the rate of sterile conjunctiva just preoperatively.

Preoperative antisepsis in ophthalmic surgery (a review)

Endophthalmitis remains a serious complication following intraocular procedures. Preoperative prophylactic measures for endophthalmitis decrease the morbidity associated with this disease and represent a standard of care prior to ophthalmic surgery. The literature supports as measures for ocular antisepsis: povidone-iodine solution for ocular surface preparation, chlorhexidine in patients with iodine allergy and application of topical antibiotics. Povidone-iodine is regarded as the most effective antiseptic associated with significant reduction in ocular surface bacterial counts. Currently, the recommended preoperative management is the application of 5% povidone-iodine solution in the conjunctival fornix, prior to surgery. This paper reviews the preoperative measures for ocular antisepsis, used in order to decrease the risk of culture-proven endophthalmitis.

Comparison of Povidone-Iodine and Gentamicin Soak as Scleral Buckle Infection Prophylaxis

Objective

To determine the best method of antimicrobial prophylaxis against implanted material-associated infections in the setting of scleral buckle surgery.

Design

Experimental study.

Participants

Scleral buckle elements were soaked in either gram-positive or polymicrobial broth, while control buckle elements were soaked in PBS only.

Methods

Solid silicone and sponge scleral buckle elements were inoculated with common pathogens of the ocular surface, and then soaked in either 1% or 5% povidone-iodine, 1 mg/mL gentamicin solution, or sterile saline for 1, 5, 10, or 15 minutes. Bacteria were then isolated from the buckle elements and cultured for 24 hours.

Results

In all gram-positive bacterial conditions, gentamicin solution decreased the bacterial load from 451,666.67 colony-forming units (CFU)/mL to 171,611.11 CFU/mL (p=0.0004). The fractional bacterial survival after soaking in gentamicin was higher for the silicone sponge than band (0.357 vs 0.079, p=0.038). Both 1% and 5% povidone-iodine were able to completely eradicate all gram-positive bacteria of both buckle elements. Only 5% povidone-iodine was able to completely sterilize all microbes on the buckle after soaking in a polymicrobial solution consisting of gram-positive, gram-negative bacteria, and fungi.

Conclusion

Povidone-iodine solution was significantly more effective at bacterial eradication compared to gentamicin solution. For all scleral buckle procedures, we recommend soaking the buckle element in 2–3% povidone-iodine solution before placement and rinsing the ocular surface with the same solution after placement.

Hypochlorous Acid 0.01% vs Povidone-Iodine 5% for Ocular Antisepsis

Purpose:

An alternative ocular antiseptic is needed for patients who do not tolerate povidone-iodine (PI). The purpose of this study is to compare the antimicrobial effect of hypochlorous acid (HA) 0.01% with PI 5% applied topically to the ocular surface.

Methods:

Swabs of the inferior conjunctiva and posterior lower eyelid margin of 40 patients were taken from both eyes and plated onto blood agar plates. One eye was treated with HA and the other with PI, and swabs were taken after 1-minute exposure. The eye treated with PI was rinsed with sterile saline and another swab was taken. Colony-forming units (CFUs) were recorded after 2 days. Patients rated the level of irritation after treatment in each eye.

Results:

HA and PI both gave significant reduction in CFUs from baseline ( P < .001 for HA and P = .002 for PI). The mean reduction in logCFU ± 95% CI was 0.850 ± 0.387 or greater for HA and 0.749 ± 0.385 or greater for PI; this was equivalent to a mean reduction of 7.1-fold or greater or 86% or greater (95% CI, 66%-94%) for HA and 5.6-fold or greater or 82% or greater (95% CI, 57%-93%) for PI. CFUs increased in 17 eyes after saline rinse. PI caused substantial irritation in 31 of the 40 participants, whereas no individuals had any irritation from topical HA.

Conclusions:

Both HA and PI were effective in reducing ocular bacterial load. Unlike PI, HA was not irritating to the eye. Saline rinse after topical PI may increase bacterial counts in some individuals.

X/Y shaped periorbital reconstructive surgery following enucleation or exenteration in dogs and cats: 24 cases (2013-2020)

OBJECTIVES

To describe the X/Y shaped periorbital reconstruction technique following enucleation or exenteration in dogs and cats and to evaluate its cosmetic and functional results.

MATERIALS AND METHODS

Medical records of dogs and cats from two different institutions that required enucleation or exenteration, followed by an additional X or Y plasty using fibrous periorbital tissue for cosmetic reasons, were retrospectively reviewed. All patients were evaluated clinically at 1-2 weeks, 2 months and 6 months. The eyelid sinking was scored as absent or present.

RESULTS

Nineteen dogs and five cats were included in the study. Twelve dogs and three cats had an enucleation, while the remaining seven dogs and two cats underwent exenteration. In the short-term follow up, three patients had periorbital oedema. Sixty days and 6 months post-surgery, two cats and two dogs showed eyelid depression. These two dogs were both dolichocephalic breeds. The rest of the patients showed no eyelid sinking, while the periorbital oedema observed in the short-term follow up in the two dogs and one cat had completely resolved. The four patients with ocular neoplasia did not have the 6 months follow up, because of fatal metastatic disease or euthanasia.

CLINICAL SIGNIFICANCE

The X/Y periorbital reconstructive procedure is quick, easy to perform and it provided satisfying long-term cosmetic results, except for four cases that developed eyelid depression.

The ocular surface bacterial contamination and its management in the prophylaxis of post cataract surgery endophthalmitis

Objective: To investigate the recent pieces of evidence regarding the bacterial ocular surface contamination and its treatment in the prophylaxis of post-cataract surgery endophthalmitis. Methods: We conducted a literature research on the topic of interest and selected the most relevant data. Results: The studies reported a relatively high rate of positive conjunctival culture and the most frequently isolated organism was Coagulase negative Staphylococcus, which is also the most common etiological agent of the postoperative endophthalmitis. The bacterial ocular surface load is influenced by age, climate, associated diseases, topical and systemic medication. The use of povidone-iodine alone or in association with levofloxacin eyedrops as prophylactic method is effective in reducing the conjunctival bacterial contamination and consequently decreases the incidence of postoperative endophthalmitis. Conclusions: Based on the current pieces of evidence, adequate treatment of the bacterial ocular surface contamination prior to cataract surgery seems to be effective in preventing endophthalmitis after cataract surgery. Abbreviations: EU = European Union, Spp. = Species, HIV = Human Immunodeficiency Virus.

Prevention of infection after corneal refractive surgery: a French survey

PURPOSE

To report the French refractive surgeons' real-life practices for preventing infection after corneal refractive surgery (photorefractive keratotomy [PRK], laser in situ keratomileusis [LASIK], and small-incision lenticule extraction).

SETTING

France.

DESIGN

Anonymous practice survey.

METHODS

The questionnaire was sent in a single email invitation to 400 declared refractive surgeons. The following information was recorded between December 2019 and April 2020, before the coronavirus pandemic: demographics data, preoperative evaluation and preparation of the patient, surgical management, immediate and postoperative protocol, and infections reported after corneal refractive surgery.

RESULTS

Eighty-three of 400 surgeons (20.75%) responded to the questionnaire; 55 (66.0%) performed more than 50 corneal refractive surgeries a year, and 25 (30.1%) performed more than 200 procedures a year. Thirty-six (43.4%) surgeons wore 3 protective items, 37 (44.6%) 2, 5 (6.0%) 1, and 5 (6.0%) zero. Seventy-seven (92.8%) surgeons used povidone-iodine for skin area disinfection and 54 (65%) for conjunctival fornix disinfection. The contact time of povidone-iodine was less than 3 minutes for 71 (85.0%) surgeons. Twenty surgeons (24.1%) reported at least 1 postrefractive surgery infection. Twenty percent of surgeons who wore sterile gloves for PRK reported postoperative infections compared with 62.5% for those who did not (P = .008). These figures were, respectively, 8.7% and 66.7% for the use of sterile gloves during LASIK (P = .002); 8.9% of surgeons who wore surgical masks for LASIK reported postoperative infections compared with 50.0% for those who did not (P = .01).

CONCLUSIONS

Practices are variable among French refractive surgeons. Wearing a surgical mask and sterile gloves during corneal refractive surgery appears to be advisable.

Hypochlorous acid antiseptic washout improves patient comfort after intravitreal injection: A patient reported outcomes study

Purpose:

Current ocular antiseptic practice for intravitreal injection (IVI) employs 5% povidone–iodine (Betadine^®) drops which frequently cause ocular discomfort and prolonged irritation. In an effort to improve comfort while maintaining efficacy, we studied a hypochlorous acid (HOCL 0.01%) spray washout prior to injection.

Methods:

Patients had received a minimum of 3 IVIs prepared with Betadine^® antisepsis prior to entry in this study. Their subsequent IVIs were prepared with Betadine^® followed by HOCL 0.01% washout. Facets of comfort were measured by a Likert-scaled questionnaire to compare their experiences after IVI.

Results:

Thirty-seven participants were enrolled. Addition of HOCL 0.01% spray after Betadine^® reduced the duration of discomfort (P = 0.001) and need for artificial tears postinjection (P = 0.003). It improved their reported quality of life (P = 0.04) and sleep (P = 0.01). There were neither HOCL-related side effects nor endophthalmitis during this study.

Conclusion:

Topical HOCL 0.01% spray after topical Betadine^® antisepsis significantly improved patient comfort following IVIs.

Antimycotic Activity of Ozonized Oil in Liposome Eye Drops against Candida spp

Purpose

This study aims to investigate the antifungal activity and mechanism of action of ozonized oil eye drops in liposomes (Ozodrop), commercialized as eye lubricant for the treatment of dry eye syndrome and eye inflammation. The activity was tested against four clinical Candida species: C albicans, C glabrata, C krusei, and C orthopsilosis.

Methods

The antifungal activity of the eye drop solution was ascertained by microdilution method in accordance with EUCAST obtaining the minimum inhibitory concentration for Ozodrop. The mechanism of action was further investigated in C albicans by measuring cell vitality, intracellular reactive oxygen species production, levels of cellular and mitochondrial (∆Ψ_m) membrane potential, and the extent of membrane lipid peroxidation.

Results

All Candida isolates were susceptible to Ozodrop with minimum inhibitory concentration values ranging from 0.195% (v/v) for C glabrata to 6.25% (v/v) for C orthopsilosis. After 1 hour of exposure at the minimum inhibitory concentration value about 30% of cells were killed, reaching about 70% at the highest Ozodrop value. After Ozodrop exposure, C albicans showed cell membrane depolarization, increased levels of lipid peroxidation, depolarized ∆Ψ_m, and increased reactive oxygen species generation.

Conclusions

The significant increases in reactive oxygen species production cause the accumulation of reactive oxygen species-associated damages leading to progressive Candida cell dysfunction.

Translational Relevance

The antifungal activity of Ozodrop was demonstrated at concentrations several times lower than the concentration that can be retrieved in ocular surface after its application. The antifungal activity of the eye drops Ozodrop would represent an interesting off-label indication for a product basically conceived as an eye lubricant.

Topical proparacaine eye drops to improve the experience of patients undergoing intravitreal injections: A randomized controlled trial

PURPOSE

We sought to evaluate whether additional topical anesthetic, specifically proparacaine 0.5%, improved patient experience with intravitreal injections without hindering antisepsis.

METHODS

A prospective, randomized controlled trial was conducted including 36 eyes of 36 patients undergoing intravitreal injections. Patients were randomized to treatment with additional topical proparacaine 0.5% versus control after undergoing informed consent. All patients prior to intravitreal injection underwent conjunctival culture after one drop of topical proparacaine 0.5% was placed. Half of patients then received an additional drop of proparacaine and then underwent a second conjunctival culture. The other half of patients had a drop of povidone iodine and then a second conjunctival culture. Intravitreal injection followed conjunctival cultures. To evaluate their experience, patients were provided with a survey.

RESULTS

In total, 36 patients were enrolled in the study. Three of 36 (8.3%) patients had positive conjunctival cultures after proparacaine eye drops alone. One of 17 (5.8%) patients had a positive conjunctival culture after a second drop of proparacaine. One of 19 (5.3%) patients had a positive culture after proparacaine and povidone iodine. By noninferiority analysis, proparacaine was inferior to povidone iodine (p = .28). Patient experience surveys did not differ between groups.

CONCLUSION

Patient perception did not significantly differ whether or not additional proparacaine drops were used prior to intravitreal injection in a randomized controlled trial. While proparacaine has some antiseptic properties, these were found to be inferior to those of povidone iodine. Therefore, while povidone iodine is essential for antisepsis, additional proparacaine drops should not interfere with antisepsis.

Prophylaxis measures for postinjection endophthalmitis

Intravitreal injections have become the most commonly performed ophthalmic procedure, transforming modern retina practice. Postinjection endophthalmitis, while rare, remains the most feared potential complication. Prophylaxis measures including topical antisepsis, hand hygiene, gloves, masks, and drapes have all been proposed to help prevent postinjection endophthalmitis; however, there remains significant variation in protocol, given the lack of agreement among retina specialists on which steps are crucial to prevent endophthalmitis. With millions of injections performed annually, collating data have helped us better understand risk factors for endophthalmitis after intravitreal injection. We summarize the consensus guidelines for intravitreal injection technique and comprehensively review the literature on prevention of postinjection endophthalmitis.

Optimizing the antisepsis protocol: Effectiveness of 3 povidone-iodine 1.0% applications versus a single application of povidone-iodine 5.0

PURPOSE

To determine the minimum effective concentration of povidone-iodine that reduces the bacterial load by 3-log₁₀, the U.S. Food and Drug Administration requirement for antiseptic agents, and to study alternative dosing schedules of povidone-iodine to optimize its bactericidal effect.

SETTING

Microbiology Laboratory, Evanston Hospital, Evanston, Illinois, USA.

DESIGN

Experimental study.

METHODS

A standard 0.5 McFarland solution of Staphylococcus epidermidis was applied to blood agar plates. The plates were treated with a single application of povidone-iodine solutions from 10.0% to 0.1% to define the range of interest. Another set of plates received 3 applications of various povidone-iodine solutions. Microbial growth was evaluated after 24 hours. Standard deviations with 99.0% and 99.9% confidence intervals for each concentration were estimated and used to estimate the minimum concentration that reduced the colony counts by at least 3-log₁₀.

RESULTS

Povidone-iodine at 2.5% and higher concentrations was effective in eliminating S epidermidis with a single application. Three 30-second applications of povidone-iodine at concentrations of 0.7% and higher resulted in at least a 3-log₁₀ reduction of colonies.

CONCLUSIONS

Povidone-iodine 5.0% has been the standard of care for preoperative ocular antisepsis for 3 decades. Povidone-iodine 0.7% was as effective as a bactericidal agent when applied multiple times. This suggests povidone-iodine 1.0%, applied in three 30-second applications for preoperative surface disinfection might be as effective for preoperative antisepsis.

Effectiveness of Povidone-Iodine 1% Eye Drop on Streptococcus pneumoniae and Escherichia coli Induced-Keratitis in Mice

Background:

Bacterial keratitis is an ophthalmic infection that may result in irreversible corneal damage. This study aimed to examine the effectiveness of povidone-iodine eye drop 1% in eye infection caused by inoculation of Streptococcus pneumoniae and Escherichia coli of mice.

Materials and Methods:

In this study, 49 adult male CBA/J mice were used that divided into seven equal groups. The corneas of all mice were scratched and infected with a clinical strain of either S. pneumoniae or E. coli topically, except control group. Subgroups received chloramphenicol 0.5% eye drop twice daily in case of S. pneumoniae infection or ciprofloxacin 0.3% eye drop every 4 hours following E. coli infection from or povidone-iodine 1% eye drop in both groups, from post infection (PI) day 3 to7. Slit lamp examinations (SLE) of the corneas and eyes were performed every day to examine detectable or intense corneal opacity and erosion.

Results:

In all infected mice, SLE scores were significantly higher than the control group on PI day 3. Scores increased steadily by time in all infected groups without treatment, reached to maximal value on PI day 7. In infected groups, treatment with either povidone-iodine 1% or chloramphenicol 0.5% or ciprofloxacin 0.3% on day 3, significantly decreased the SLE scores on PI day 7.

Conclusion:

Povidone-Iodine 1% was effective to decrease S. pneumoniae and E. coli induced-keratitis symptoms in mice. Treatment with povidone-iodine 1% was observed time-dependently and was comparable to common eye drop antibiotics.

The Impact of Prefilled Syringes on Endophthalmitis Following Intravitreal Injection of Ranibizumab

PURPOSE

To compare the rates of infectious endophthalmitis following intravitreal injection of ranibizumab using prefilled syringes vs conventional preparation.

DESIGN

Multicenter retrospective cohort study.

METHODS

All eyes receiving intravitreal injection of 0.5 mg ranibizumab for retinal vascular diseases at 10 retina practices across the United States (2016 to 2017) and Japan (2009 to 2017) were included. The total numbers of eyes and injections were determined from billing codes. Endophthalmitis cases were determined from billing records and evaluated with chart review. Primary outcome was the rate of postinjection acute endophthalmitis. Secondary outcomes were visual acuity and microbial spectrum.

RESULTS

A total of 243 754 intravitreal 0.5 mg ranibizumab injections (165 347 conventional and 78 407 prefilled) were administered to 43 132 unique patients during the study period. In the conventional ranibizumab group, a total of 43 cases of suspected endophthalmitis occurred (0.026%; 1 in 3845 injections) and 22 cases of culture-positive endophthalmitis occurred (0.013%; 1 in 7516 injections). In the prefilled ranibizumab group, 12 cases of suspected endophthalmitis occurred (0.015%; 1 in 6534 injections) and 2 cases of culture-positive endophthalmitis occurred (0.0026%; 1 in 39 204 injections). Prefilled syringes were associated with a trend toward decreased risk of suspected endophthalmitis (odds ratio 0.59; 95% confidence interval 0.31-1.12; P = .10) and a statistically significant decreased risk of culture-positive endophthalmitis (odds ratio 0.19; 95% confidence interval 0.045-0.82; P = .025). Average logMAR vision loss at final follow-up was significantly worse for eyes that developed endophthalmitis from the conventional ranibizumab preparation compared to the prefilled syringe group (4.45 lines lost from baseline acuity vs 0.38 lines lost; P = .0062). Oral-associated flora was found in 27.3% (6/22) of conventional ranibizumab culture-positive endophthalmitis cases (3 cases of Streptococcus viridans, 3 cases of Enterococcus faecalis) compared to 0 cases in the prefilled ranibizumab group.

CONCLUSION

In a large, multicenter, retrospective study the use of prefilled syringes during intravitreal injection of ranibizumab was associated with a reduced rate of culture-positive endophthalmitis, including from oral flora, as well as with improved visual acuity outcomes.

Polyvinyl alcohol-iodine induced corneal epithelial injury in vivo and its protection by topical rebamipide treatment

Periocular povidone-iodine (PI) and polyvinyl alcohol-iodine (PAI) have had a major role in the prevention of endophthalmitis. The purpose of this study was to investigate the corneal epithelial toxicity of PAI in a rabbit eye model using corneal resistance (CR) measurement, which is a good indicator of cell barrier function. Rabbit eyes were administered PAI solution at 4-, 6-, 8-, or 16-fold dilution with physiological saline solution (saline) or saline alone (control), to the conjunctival sac with/without wash-out with saline. Corneal epithelial injury assessed by fluorescein staining and the CR ratio was measured at 10 minutes (min) to 96 hours (h) after the initial administration. Histological observation was performed in the eyes following the PAI or control administrations. At 120 min after administration of PAI solution, the CR ratio was decreased and superficial punctate keratopathy (SPK) was significantly increased in each of the PAI-administered groups compared to the control. Recovery of CR and SPK after administration of 6- or 8-fold dilution of PAI was significantly delayed in eyes that were not subsequently washed with saline compared with eyes that were. Pre- or post-instillation of 2% rebamipide ophthalmic suspension significantly reduced PAI induced-SPK and -decrease of CR ratio. The CR method was able to accurately and quantitatively evaluate fine corneal epithelial injury. It is suggested that eyes should be washed with saline solution after administration of PAI solution or the instillation of rebamipide to prevent or reduce corneal epithelial injury.

Management of giant fornix syndrome with irrigation with povidone-iodine

Giant fornix syndrome (GFS) was first described as a cause for a relapsing mucopurulent conjunctivitis. Predominantly elderly patients have enlarged superior fornices from superior aponeurosis dehiscence that permits the accumulation of protein coagulum that is colonised by bacteria. Established treatment includes the use of intensive topical antibiotic and corticosteroid. We describe a case of a 98-year-old woman with GFS who did not respond to several weeks of intensive (two hourly) treatment with topical prednisolone 1% drops and chloramphenicol. Subsequent additional regular sweeping of the fornices with cotton buds and topical medication did not improve her symptoms but which resolved with manual coagulum debridement and application of 10% povidone-iodine. This treatment offers an effective treatment option of GFS cases, which do not respond to intensive topical corticosteroids and chloramphenicol.

Ocular flora and their antibiotic susceptibility in patients having cataract surgery in Italy

PURPOSE

To characterize the ocular flora in a consecutive group of patients having cataract surgery and to determine the antibiotic susceptibility profile of isolates to several ophthalmic antibiotics.

SETTING

Hospital Di Stefano, Catania, Italy.

DESIGN

Observational case series.

METHODS

Conjunctival and eyelid cultures from patients were obtained 14 days before surgery and, if positive, repeated the day of the surgery. Antimicrobial susceptibility for aminoglycosides (netilmicin and tobramycin), fluoroquinolones (ofloxacin, levofloxacin, and moxifloxacin), chloramphenicol, and azithromycin was tested using the Kirby-Bauer disk diffusion method. Susceptibility was also tested for oxacillin, cefuroxime, and vancomycin. All positive patients received a 2-day preoperative course of 3 mg/mL netilmicin ophthalmic solution 4 times a day. The recovery rate of microorganisms after antibiotic treatment compared with baseline was calculated.

RESULTS

One hundred twenty consecutive patients were included in the study. Cultures were positive in 72.5% of patients; 131 isolates, mainly gram-positive, were identified. Staphylococcus epidermidis (58.0%) and Staphylococcus aureus (15.3%) were the most frequently isolated microorganisms. Methicillin-resistant staphylococci accounted for 3.8% of S epidermidis and 20.0% of S aureus. A high in vitro susceptibility (>90%) for all isolates, including multiresistant coagulase-negative Staphylococcus, was obtained for netilmicin, vancomycin, and cefuroxime. The recovery rate of isolates before surgery was reduced by 93.9% (P < .001).

CONCLUSIONS

Conjunctival and lid margin isolates were sensitive to netilmicin, vancomycin, and cefuroxime. Microorganisms were less susceptible to other ophthalmic antibiotics, with the exception of moxifloxacin. A 2-day preoperative course with topical netilmicin reduced most bacteria identified on the conjunctiva and eyelids.

FINANCIAL DISCLOSURE

Dr. Papa and Ms. Blanco are employees of Società Industria Farmaceutica Italiana SpA. Dr. Santocono has no financial or proprietary interest in any material or method mentioned.

Infection following strabismus surgery

PURPOSE OF REVIEW

To provide the most up to date information on postoperative infection associated with strabismus surgery, its diagnosis, management, and prevention.

RECENT FINDINGS

Recent studies show that topical povidone-iodide is effective in reducing the bacteria colony count at the incision site and preventing contamination during strabismus surgery. Repeating povidone-iodide 5% drops after surgical preparation and presoaking the sutures in povidone-iodide reduces bacterial contamination further. There is no single postoperative day that would be best to detect the onset of a postoperative infection. Infection can follow a normal postoperative visit.

SUMMARY

Infection continues to be a concerning complication of strabismus surgery. Early detection and treatment is needed to obtain a good outcome. Patients and their families should be educated on the early signs and symptoms of postoperative infection and to contact their ophthalmologist if any occur.

Preoperative preparation of eye with chlorhexidine solution significantly reduces bacterial load prior to 23-gauge vitrectomy in Swedish health care

Background

Bacteria in the conjunctiva present a potential risk of vitreous cavity infection during 23-gauge pars plana vitrectomy (PPV). Current preoperative procedures used in Sweden include irrigation with chlorhexidine solution (CHX) 0.05% only and no iodine solutions. We evaluated the bacterial diversity and load before and after this single antibacterial measure.

Methods

In a prospective, consecutive cohort we investigated bacterial growth in samples from 40 eyes in 39 consecutive individuals subjected to vitrectomy. A conjunctival specimen was collected from each preoperative patient before and after irrigating of eye with CHX, 0.05% solution. Iodine was not used during any part of the surgery. One drop of chloramphenicol was administered prior to surgery. Samples from vitreous cavity were collected at the beginning and end of vitrectomy. All conjunctival specimens were cultured for different species and quantified using colony forming units (CFU).

Results

There was a significant 82% reduction in the total number of CFUs for all bacteria in all eyes (P < 0.0001), and 90% reduction for coagulase negative staphylococci (CoNS) alone (P = 0.0002). The number of eyes with positive bacterial growth in conjunctival samples decreased from 33 to 18 after irrigation with CHX (P = 0.0023). The most common bacteria prior to surgery were CoNS (70%), Propionibacterium acnes (55%) and Corynebacterium species (36%). No case of post-vitrectomy endophthalmitis was reported during mean follow-up time, which was 4.6 ± 2.3 (range; 1.5 to 9) months.

Conclusions

Patients undergoing PPV harbored bacteria in conjunctiva capable of causing post-vitrectomy endophthalmitis. Preoperative preparation with CHX significantly reduced the bacterial load in the conjunctival samples subsequently leading to very low inoculation rates in recovered vitreous samples. Thus, CHX used as a single disinfectant agent might be an effective preoperative procedure for eye surgery in Sweden. This is a relatively small study but the results could be a reference for other intraocular surgeries.

The Routine Use of Intracameral Antibiotics to Prevent Endophthalmitis After Cataract Surgery: How Good is the Evidence?

Post-operative endophthalmitis (POE) following cataract surgery is an uncommon, vision-threatening complication that has been reported to occur at rates of between approximately 0.03% and 0.2%. Prompt diagnosis and treatment of endophthalmitis is critical for minimizing vision loss, but most recent efforts have focused on the prophylactic administration of antibiotics to prevent the development of endophthalmitis. Surgeons from around the world have different topical and intracameral antibiotic usage patterns to prevent endophthalmitis, and to date no general consensus regarding best practice has emerged. Several studies have reported on the routine use of intracameral cefuroxime, moxifloxacin, and vancomycin, including a single randomized clinical trial by the European Society of Cataract and Refractive Surgery (ESCRS) in 2007. These studies have notable shortcomings, but many authors suggest that intracameral cefuroxime together with topical antibiotics probably decreases the risk of endophthalmitis. However, the deleterious effects of routine prophylactic antibiotics, which include toxicity, cost, and increasing antimicrobial resistance, among others, are noteworthy. In contrast, aseptic technique with pre-operative instillation of povidone-iodine remains the only technique supported by level I evidence to reduce the incidence of endophthalmitis. Although the routine use of intracameral antibiotics continues to increase throughout the world, data from multicenter, randomized, prospective trials is needed to provide better guidance regarding the prophylactic use of antibiotics.

Povidone-iodine concentration and dosing in cataract surgery

Iodine has been recognized as an effective bactericide since the 1800s, and povidone-iodine (PI) solution has been applied to the ocular surface and periocular skin since the 1980s to prevent endophthalmitis in cataract surgery. In vitro, PI solution kills bacteria quickly at dilute concentrations (0.05%-1.0%). In many instances, PI kills bacteria more quickly at these dilute concentrations than more conventional (5%-10%) concentrations. This is due to greater availability of diatomic free iodine in dilute solution, the bactericidal component of PI. The toxicity of PI, both in vitro and clinically, has been shown to be related to concentration. Current American Academy of Ophthalmology and the European Society of Cataract and Refractive Surgeons recommendations regarding PI use suggest using 5% PI before surgery. An alternative dosing strategy uses dilute PI repetitively throughout cataract surgery (0.25% every 30 seconds). We review the povidone-iodine literature with attention to basic science and use of dilute PI.

The Efficacy of 5% Povidone-Iodine for 3 Minutes Prior to Cataract Surgery

Purpose

To evaluate the efficacy of 3 minutes of 5% povidone-iodine for skin and conjunctival antisepsis prior to cataract surgery as recommended by the European Society of Cataract and Refractive Surgeons.

Methods

A prospective controlled study of 54 patients undergoing unilateral cataract surgery by phacoemulsification was undertaken. The eye undergoing surgery was prepared with 5% povidone-iodine for 3 minutes. The other eye served as control. Swabs were taken from both eyes prior to application of 5% povidone-iodine and 3 minutes after. Proportion of culture-positive swabs, mean number of species, and growth of isolates on culture were compared at different times and between the two groups.

Results

Coagulase-negative Staphylococcus (CoNS) was the main species isolated from culture-positive swabs. Use of 5% povidone-iodine for 3 minutes resulted in a statistically significant reduction in proportion of culture-positive swabs (87% vs 30%, p<0.001), mean number of species (0.96±0.47 vs 0.30±0.46, p<0.001), and growth of CoNS (heavy: 30% vs 0%, moderate: 23% vs 6%, light: 47% vs 94%, p=0.004). No such changes were observed in the control group.

Conclusions

Use of 5% povidone-iodine for 3 minutes prior to cataract surgery achieves a significant reduction in organisms such as CoNS from lid and conjunctival flora.

Endophthalmitis Caused byMycobacterium Abscessus

PURPOSE

To describe the clinical and laboratory features of a case of endophthalmitis caused by Mycobacterium abscessus in a patient immunocompetent.

METHODS

case report. A 65-year-old woman with bilateral cataracts was treated by surgery with phacoemulsification and posterior chamber lens implantation.

RESULTS

The funduscopic examination showed vitreous cells over the optic nerve head, chorioretinal infiltrates, and focal vasculitis. Vitreous humor aspirate disclosed acid-fast bacilli. In the culture on Löwenstein-Jensen medium grew colonies identified as M. abscessus.

CONCLUSIONS

M. abscessus is cause of endophthalmitis and crystalline keratopathy. Risk factor include surgical intervention or exogenous contamination. Our patient has no systemic pathology predisposing to the development of endophthalmitis.

Comparative efficacy of two different topical povidone-iodine 5% regimens in reducing conjunctival bacterial flora: A randomized parallel double-masked clinical trial

INTRODUCTION

The increasing prevalence of multi-resistant bacteria is a major public health concern. Infections acquired during ophthalmic surgery are devastating. The purpose of the current study is to compare the proportion of eyes with negative bacterial cultures on all tested media after 1 versus 3 sequential drops of povidone-iodine (PI) 5% into the inferior conjunctival fornix.

METHODS

Patients were randomly assigned to receive 1 (PI group) drop (at time 28 minutes) or 3 (PI plus group) sequential drops (at time 0, 20 minutes and 28 minutes) of PI 5% into the inferior conjunctival sac of one randomly selected eye. A swab culture was obtained from the inferior conjunctival fornix 5 minutes before and 30 minutes after time 0. Central corneal thickness (CCT) was measured shortly before time 0 and shortly after time 30. Conjunctival swabs were incubated aerobically in enriched Thioglycolate liquid medium (meat broth) and in three solid culture media (chocolate agar, trypticase soy agar with 5% sheep blood, and Sabouraud agar).

RESULTS

There was no significant difference in the proportion of negative cultures after intervention between groups (p = 0.1638). Also in the PI group (n = 59), the proportion of eyes with negative cultures after PI (79.7%) did not differ significantly from baseline (76.3%; p = 0.7539). However in the PI plus group (n = 61), the proportion of eyes with all negative cultures after PI (85.3%) was significantly higher than before PI (70.5%) (p = 0.0177). There was no significant difference in mean CCT before and after the intervention in both groups.

CONCLUSION

Instillation of 3 sequential drops of PI was associated with a significant increase in the proportion of eyes with all negative cultures, while instillation of a single drop of PI was not associated with a significant increase in the proportion of negative cultures. Further study is warranted to determine whether the difference between the PI administration regimens is also associated with differences in the rates of postoperative ocular infections.

Effectiveness of meibomian gland massage combined with topical levofloxacin against ocular surface flora in patients before penetrating ocular surgery

OBJECTIVE

To investigate the bacterial profile in the conjunctiva and meibomian glands in patients before penetrating ocular surgeries, and to compare the anti-bacterial efficacy of 0.5% levofloxacin and its combination with meibomian gland massage.

DESIGN

Hospital-based, case-control study.

PARTICIPANTS

Two hundred and twenty-six eyes from 226 patients with non-infective ocular diseases and scheduled for penetrating ocular surgeries.

METHODS

Tested eyes were administered topical 0.5% levofloxacin (4 times daily) for 2 days. Among them, 91 eyes received meibomian gland massage before levofloxacin application. Samples from the conjunctival sac and meibomian glands were collected for aerobic and anaerobic cultures.

MAIN OUTCOME MEASURES

Culture-positivity and bacterial strains.

RESULTS

Before treatment, aerobes and anaerobes were cultured from 38.5% and 11.0% of the conjunctival samples respectively, compared with 38.5% and 8.8% in the meibomian secretions respectively. Staphylococcus epidermidis and Propionibacterium acnes were the commonest isolated aerobe and anaerobe. Two-day application of levofloxacin reduced aerobic growth to 29.6% in the conjunctiva and 19.3% in the meibomian glands. It had no effect on the anaerobes in these regions (13.3% in the conjunctiva and 10.4% in the meibomian glands). Combined levofloxacin with meibomian gland massage further reduced aerobic growth to 19.8% in the conjunctiva and 11.0% in the meibomian glands. It also drastically decreased anaerobic growth in the meibomian glands (1.1%).

CONCLUSIONS

Meibomian glands carrying considerable bacteria should be considered as a potential source of contamination in ocular surgery. Meibomian gland massage shows additional anti-bacterial effects to topical levofloxacin and could be recommended as a complementary preoperative prophylaxis.

Timing of Povidone-Iodine Application to Reduce the Risk of Endophthalmitis after Intravitreal Injections

PURPOSE

To analyze comparatively the effect of different intravitreal injection (IVI) protocols on the incidence of endophthalmitis occurring after injection.

DESIGN

Retrospective case-control series.

PARTICIPANTS

Twenty-seven retina specialists in a large vitreoretinal practice performed 37 646 IVIs.

METHODS

Multivariate analysis was used to identify risk factors for development of endophthalmitis occurring after injection. Before all injections, a technician applied 5% povidone-iodine (PI) to the eyelids and conjunctiva. There were 4 distinct aseptic protocols with regard to reapplication of PI by physicians: physicians who did not reapply PI, reapplication of PI without the use of a lid speculum, reapplication of PI before speculum placement, and reapplication of PI after speculum placement. Other analyzed variables included the use of gloves, a caliper to mark the injection site, and the class of medication (steroid vs. anti-vascular endothelial growth factor).

MAIN OUTCOME MEASURES

Cases of presumed infectious endophthalmitis.

RESULTS

Thirty-three cases of presumed infectious endophthalmitis occurred after 37 646 injections (0.088%). The method of PI application was found to be a statistically significant predictor of the incidence of endophthalmitis (P = 0.031). When compared with the incidence of endophthalmitis for physicians who did not reapply PI (0.124% [20/16 155]), there was no statistical difference for reapplication of PI without the use of a speculum (0.110% [6/5472]; P = 0.584) or reapplication before speculum insertion (0.122% [5/4067]; P = 0.863). However, reapplication of PI after insertion of the lid speculum was associated with a significantly decreased incidence of endophthalmitis (0.017% [2/11 952]; P = 0.004; odds ratio, 0.113). Use of gloves (P = 0.119) or a caliper to mark the injection site (P = 0.496) and the class of medication (P = 0.740) were not found to be statistically significant risk factors for endophthalmitis development.

CONCLUSIONS

The application of PI after placement of the lid speculum reduced the incidence of endophthalmitis occurring after injection approximately 7-fold compared with other aseptic protocols. Preventing the eyelid from contacting the injection site after the final application of PI is an important step in improving the safety of intravitreal injections.

A retrospective analysis of the risk factors for surgical site infections and long-term follow-up after transpalpebral enucleation in horses

Background

Implants are often used to improve the cosmetic appearance of horses after enucleation of the eye. When surgical site infection (SSI) occurs, the implant will almost always be lost. The aim of this study is to collect data on the risk factors for SSIs and report long-term follow-up (cosmetic results and return to work) after transpalpebral enucleations. In this retrospective study, records of horses undergoing transpalpebral enucleation were reviewed (2007–2014) and telephone interviews were used to obtain long term follow-up. The potential risk factors for SSIs (indication for enucleation, use of an implant, standing procedures, duration of surgery, opening of the conjunctival sac and prolonged use of antimicrobials) were analysed for their association with the outcome measure ‘SSI’ vs ‘no SSI’ by multivariable binary logistic regression testing. Indications for enucleation were grouped as follows: Group 1 (clean) included equine recurrent uveitis, too small or too large globes, and intraocular tumours, Group 2 (non-clean) included corneal perforation/rupture and infected ulcers and Group 3 (tumour) included extraocular tumours.

Results

One hundred and seven cases of enucleation were evaluated. An implant was used in 49 horses. The overall number of SSIs was 8 (7.5%). Multivariable logistic regression testing showed implants (OR 7.5, P = 0.04) and standing procedures (OR 12.1; P = 0.03) were significantly associated with the percentage of SSIs and increased the risk of SSI. The eyes of horses in Groups 2 and 3 trended towards a larger risk for developing SSIs (OR 4.9; P = 0.09 and OR 5.9; P = 0.1, respectively). Prolonged use of antimicrobials, long surgery times and the opening of the conjunctival sac during dissection did not show significant associations with SSI risk.

Conclusions

The risk of SSI after enucleation is low in clean eyes and when no implant is used. Placing an implant or performing a standing enucleation significantly increases the risk of SSIs. Although implants can be used for eyes that fall into Groups 2 and 3, 17% of the horses in these two groups developed an SSI leading to loss of the implant.

Importance of Lid Hygiene Before Ocular Surgery: Qualitative and Quantitative Analysis of Eyelid and Conjunctiva Microbiota

Objective:

To evaluate the efficacy of a cleansing eyelid wipe in reducing the microbiota present on the ocular surface before cataract surgery.

Methods:

A single-center, prospective, single-blind phase IV study was conducted at the University Complutense of Madrid. Forty-five adult patients who were scheduled for ocular surgery after treatment with commercially available eyelid wipes were consecutively enrolled. The study lasted 5 days and the patients were examined at day 0 (D0), day 3 (D3), and day 5 (D5). They received instructions to apply the eyelid wipe only to the eye subject to surgery, using the other eye as a control with no treatment. Lid and conjunctival swabs were taken on each day and microbes identified. Ocular surface microbiota was estimated by measuring the area of the agar plate occupied by the grown colonies with respect to the total available area.

Results:

Measurements at D3 and D5 showed a percent reduction of 58% and 63%, respectively, in the microbial load on the eyelid in the treated eyes (P=0.0011). There was also a reduction, although nonsignificant, in the microbiota of the conjunctiva of 72% and 69% on D3 and D5, respectively.

Conclusions:

The degree of microbiota reduction was comparable with that obtained after topical application of antibiotics in other studies. The results suggest the use of these eyelid wipes as a complementary prophylactic method before any ocular surgery.

Prospective, Randomized Clinical Trial of Povidone-Iodine 1.25% Solution Versus Topical Antibiotics for Treatment of Bacterial Keratitis

PURPOSE

To compare povidone-iodine 1.25% ophthalmic solution with topical antibiotics for treatment of bacterial keratitis in areas of the world where use of effective topical antibiotics may not be an option.

STUDY DESIGN

Randomized, controlled, investigator-masked clinical trial.

METHODS

We randomized 172 individuals with bacterial keratitis to topical treatment with povidone-iodine or antibiotics (neomycin-polymyxin B-gramicidin in the Philippines; ciprofloxacin 0.3% in India). Using survival analysis, we compared intervals from start of treatment to "presumed cure" (primary outcome measure, defined as a closed epithelial defect without associated inflammatory signs) and to "recovering" (residual epithelial defect <1 mm² with only minimal inflammation).

RESULTS

Median interval to presumed cure in the Philippines was 7 days for povidone-iodine and 7 days for neomycin-polymyxin B-gramicidin (95% confidence interval [CI] for difference in median interval, -9.5 to 0.7 days) and in India was 12 days for povidone-iodine and 17 days for ciprofloxacin (95% CI, -35.2 to 3.2 days). Hazard ratio (HR) for presumed cure among those treated with povidone-iodine (vs antibiotics) was 1.46 in the Philippines (95% CI, 0.90-2.36; P = .13) and 1.70 in India (95% CI, 0.73-3.94; P = .22). Comparisons of intervals to recovering and HR for recovering also revealed no significant differences between treatment groups in either country.

CONCLUSIONS

There is no significant difference between the effect of topical povidone-iodine 1.25% and topical antibiotics commonly available in the developing world for treatment of bacterial keratitis. Povidone-iodine 1.25%, which is widely available and inexpensive, can be considered for treatment of bacterial keratitis when antibiotic treatment is not practical.

Vancomycin in infusion during vitrectomy in surgical treatment of acute postoperative and posttraumatic endophthalmitis

Background

Endophthalmitis is potentially devastating intraocular inflammation following eye trauma or surgery. We describe the visual outcomes and causative pathogens in acute bacterial postoperative and posttraumatic endophthalmitis treated with immediate pars plana vitrectomy (PPV) with Vancomycin dissolved in the infusion fluid.

Methods

Clinical records of consecutive 30 patients with postoperative endophthalmitis and 15 patients with posttraumatic endophthalmitis were evaluated. Vancomycin was administered constantly in the infusion fluid at the time of complete PPV. Cultures were prepared from anterior chamber paracentesis. The mean follow-up period was 13 months.

Results

The visual acuities were improved in 38 cases (84 %) and remained stable in seven cases (16 %). Median post-PPV visual acuity was 1.0 logMAR in a group with postoperative endophthalmitis and 1.3 logMAR in a group with posttraumatic endophthalmitis (p < 0.05). Twenty cases (44 %) were culture-positive (Staphylococcus, Streptococcus, Enterococcus and Bacillus spp).

Conclusions

Early PPV with Vanomycin in infusion leads to vision improvement in patients with both posttraumatic and postoperative endophthalmitis. In our series of 45 cases culture was positive only in half of the cases.

Selected Antimicrobial Activity of Topical Ophthalmic Anesthetics

PURPOSE

Endophthalmitis is a rare complication of intravitreal injection (IVI). It is recommended that povidone-iodine be the last agent applied before IVI. Patients have reported povidone-iodine application to be the most bothersome part of IVIs. Topical anesthetics have been demonstrated to have antibacterial effects. This study compared the minimum inhibitory concentration (MIC) of topical anesthetic eye drops (proparacaine 0.5%, tetracaine 0.5%, lidocaine 2.0%) and the antiseptic, 5.0% povidone-iodine, against two organisms causing endophthalmitis after IVI.

METHODS

Minimum inhibitory concentration values of topical anesthetics, povidone-iodine, preservative benzalkonium chloride (0.01%), and saline control were determined using five isolates of each Staphylococcus epidermidis and viridans group Streptococcus species (VGS). A broth microdilution technique was used with serial dilutions.

RESULTS

Lidocaine (8.53 × 10^-5mol/mL) had MICs of 4.27 to 8.53 × 10^-5 mol/mL, and tetracaine (1.89 × 10^-5 mol/mL) had MICs of 9.45 × 10^-6 mol/mL for all isolates. Proparacaine (1.7 × 10^-5 mol/mL) had MICs of 1.32 to 5.3 × 10^-7 and 4.25 × 10^-6 mol/mL for S. epidermidis and VGS, respectively). Benzalkonium chloride (3.52 × 10^-7 mol/mL) had MICs of 1.86 × 10^-9 to 1.1 × 10^-8 and 4.40 × 10^-8 mol/mL for S. epidermidis and VGS, respectively. Povidone-iodine (1.37 × 10^-4 mol/mL) had MICs of 2.14 to 4.28 × 10^-6 and 8.56 × 10^-6 mol/mL for S. epidermidis and VGS, respectively.

CONCLUSION

Proparacaine was the anesthetic with the lowest MICs, lower than that of povidone-iodine. Benzalkonium chloride had lower MICs than proparacaine. All tested anesthetics and povidone-iodine inhibited growth of S. epidermidis and VGS at commercially available concentrations.

TRANSLATIONAL RELEVANCE

For certain patients, it could be possible to use topical anesthetic after povidone-iodine for comfort without inhibiting and perhaps contributing additional antimicrobial benefit.

Comparison of 1-day versus 1-hour application of topical neomycin/polymyxin-B before cataract surgery

PURPOSE

To compare the efficacy of 2 prophylaxis regimens before cataract surgery using topical antibiotics (1 hour before surgery versus the day before), both with povidone-iodine, with regard to reducing the preoperative conjunctival bacterial load.

SETTING

Tertiary ophthalmic referral center, Munich, Germany.

DESIGN

Prospective comparative case series.

METHODS

Eyes were treated with topical antibiotics and their conjunctival sac flush irrigated using 10 mL of povidone-iodine 1.0%. All eyes were randomized to receive either 4 applications of topical 3500 IU/mL neomycin sulfate/6000 IU/mL polymyxin-B sulfate within 1 hour preoperatively (Group 1) or on the day before surgery (Group 2). Conjunctival specimens were obtained at 4 timepoints: T0C untreated fellow eye (control), T0 surgery eye (after antibiotic prophylaxis but before povidone-iodine irrigation), T1 after povidone-iodine, and T2 at the conclusion of surgery. All specimens were inoculated onto blood and chocolate-blood agar and into thioglycollate broth.

RESULTS

One hundred thirty-three eyes of 133 consecutive patients were included (Group 1, 64 eyes; Group 2, 69 eyes). The antibiotic regimens were equally effective in reducing the aerobic and microaerophilic conjunctival flora (Group 1, P=.028; Group 2, P=.000), but had no significant effect on anaerobic bacteria (Group 1, P=.201; Group 2, P=.117). Flush irrigation of the conjunctival sac using 10.0 mL povidone-iodine 1.0% significantly decreased the conjunctival bacterial load in both groups.

CONCLUSION

Topical neomycin/polymyxin-B was equally effective in reducing the conjunctival bacterial load whether given 1 day or 1 hour before surgery. The greatest effect was achieved by irrigating the conjunctival sac using povidone-iodine.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Study of the Acute Effects of Povidone-Iodine on Conjunctival Bacterial Flora

PURPOSE

The purpose of this laboratory study was to assess the effect of povidone-iodine (PI) use topically on the conjunctiva in regard to needle bore contamination and to compare these results with our previous findings from an evaluation of bacterial contamination following gatifloxacin and moxifloxacin administration.

METHODS

We performed 100 conjunctival 27-gauge needle penetrations of both eyes of 13 fresh cadavers. Eyes were then soaked in 10% PI, after which conjunctiva was again penetrated 100 times. After conjunctival penetration, the needles were irrigated, and the irrigant was assessed for bacterial growth. Results were compared with previous work assessing fluoroquinolone effectiveness through the same model.

RESULTS

We observed a 28% (P = 0.003) decrease in bacterial growth and 40% (P < 0.0001) decrease in colony counts after PI placement. Differences between the effect of PI versus moxifloxacin and gatifloxacin were not statistically significant.

CONCLUSIONS

There is a greater decrease in bacterial load after treatment with PI for surface cultures than for cultures obtained through a needle bore passed through the conjunctiva. PI is a superior approach to topical antibiotics to decrease conjunctival bacterial load.

Endophthalmitis following intravitreal anti-vascular endothelial growth factor (VEGF) injection: a comprehensive review

The purpose of this review is to report and summarize previously reported studies and assess many of the individual steps of the intravitreal injection procedure's possible effect on the prevention of endophthalmitis. The pooled endophthalmitis rate from 20 large retrospective case series of anti-VEGF injections was 144/510,396 (0.028%; 1/3,544). Injections may be performed in an office-based location or in an operating room (OR) and low rates of endophthalmitis can be achieved in either location with careful attention to asepsis. Pre- or post-injection topical antibiotics have not been shown to be effective, and could select for more virulent microorganisms. Povidone-iodine prior to injection is accepted as the gold-standard antiseptic agent, but aqueous chlorhexidine may be an alternative. Antisepsis before and after gel or subconjunctival anesthetic is suggested. The preponderance of Streptococcal infections after intravitreal injection is discussed, including the possible role of aerosolization, which can be minimized by using face masks or maintaining silence. As with other invasive procedures in medicine, the use of sterile gloves, following adequate hand antisepsis, may be considered. Control of the eyelashes and lid margin is required to avoid contamination of the needle, but this can be achieved with or without a speculum. Techniques to minimize vitreous reflux have not been shown to reduce the risk of endophthalmitis. Same day bilateral injections should be performed as two separate procedures, preferably using drug from different lots, especially when using compounded drugs.

Dual application versus single application of povidone-iodine in reducing surgical site contamination during strabismus surgery

PURPOSE

To investigate the contamination rates in patients undergoing strabismus surgery who received a single versus a dual application of povidone-iodine.

METHODS

Patients undergoing strabismus surgery were divided into two groups of approximately equal size. Prior to surgery, the surgical sites for both groups were prepared by applying 4 drops of povidone-iodine 5% directly into the conjunctival fornices, after which the eyelashes were cleaned with cotton tips soaked with povidone-iodine 5%. Sterile gauze pads soaked with povidone-iodine 5% were used to clean the periocular skin. After lid speculum placement, the patients in the dual application group received an additional 2 drops of povidone-iodine in the conjunctival fornices. Intraoperatively, the conjunctiva, sclera, needles/sutures, and lid speculum were cultured. Gram stain and cultures were obtained and quantified. Contamination was defined as any bacterial growth on blood agar plates at 2 days.

RESULTS

A total of 104 patients (aged 7 months to 79 years) were included. The single application group had a 25% contamination rate of surgical site and sutures; the dual application group, a 10% contamination rate. This difference was statistically significant (P = 0.03). The rate of eyelid speculum contamination was unaffected by additional applications (12.5% contamination rate in both groups [P = 0.5]). The additional application of povidone-iodine affected the contamination rate of the conjunctival incision site the most, with a decrease from 20.5% to 5% (P = 0.02).

CONCLUSIONS

In our study cohort a second application of povidone-iodine significantly decreased the rate of contamination of the surgical site and sutures. It did not affect contamination of the lid speculum.

Effectiveness of antimicrobial peptide immobilization for preventing perioperative cornea implant-associated bacterial infection

Titanium (Ti) is a promising candidate biomaterial for an artificial corneal skirt. Antimicrobial peptide (AMP) immobilization may improve the bactericidal effect of the Ti substrate. In this study, we tested the bactericidal efficacy of a functionalized Ti surface in a rabbit keratitis model. A corneal stromal pocket was created by a femtosecond laser. The Ti films were then inserted into the pocket, and Staphylococcus aureus or Pseudomonas aeruginosa was inoculated into the pocket above the implant films. The corneas with Ti-AMP implants were compared with the corneas implanted with unprotected Ti by slit lamp observation and anterior segment optical coherence tomography (AS-OCT). Inflammatory responses were evaluated by bacterium counting, hematoxylin-eosin staining, and immunostaining. There was a lower incidence and a lesser extent of infection on rabbit corneas with Ti-AMP implants than on those with unprotected Ti implants. The bactericidal effect of AMP against S. aureus was comparable to that of postoperative prophylactic antibiotic treatment; hence, SESB2V AMP bound to the Ti implant provided functional activity in vivo, but its efficacy was greater against S. aureus than against P. aeruginosa. This work suggests that SESB2V AMP can be successfully functionalized in a rabbit keratitis model to prevent perioperative corneal infection.